This invention relates to a mixing head for the mixing of at least two components forming a synthetic material.
In a known mixing head of this kind for the mixing of components of synthetic material which form a foamed synthetic material, in particular, a polyurethane foam during their chemical reactions, the throttling member is formed by a throttle slider with a through-hole having a diameter which corresponds to the diameter of the guide channel or discharging channel. In the correspondingly aligned position of the through-bore of the throttle slider with the channel, a mechanical cleaning of the mixing chamber and the discharging channel is possible by means of a discharging piston, whereas with respect to the channel transversally off-set position of the through-hole of the throttle slider, by formation of a tapered over-flow opening between the mixing chamber and the inside of the through-hole, there is formed a turbulence chamber on the inside of the bore, by means of which the mixing intensity of the reaction components should be improved. Because of the configuration of such a turbulence chamber, there results great turbulence of the liquid mixture of the components, which turbulence, even in a discharging channel of constant cross-section, does not undergo any stabilization after leaving the turbulence chamber sufficient to prevent defects in the product, in particular air occlusions occur.
Furthermore, there is known a mixing head for the production of a chemically reactive mixture consisting of at least two components of a synthetic material of the indicated kind, which mixing head has a throttle member consisting of several baffle barriers which are aligned in a row or off-set next to one another and/or behind one another, which baffle barriers can be inserted into the mixing chamber from the opposite sides of the mixing chamber. An advantageous mechanical self-cleaning of the discharging channel and the mixing chamber by means of the discharging piston is also attained in this case when the baffle barriers are pulled out of the mixing chamber. However, in this known case, the liquid mixture of the components being forced through a multitude of squeezer slits and being injected at high speed into the mixing chamber does not undergo a sufficient reduction of the resulting turbulence which therefore results in defects in the product to be produced, in particular, in shaped products.